<!DOCTYPE html>
<html lang="zh" dir="ltr" class="client-nojs">
<head>
<title>非静态成员函数</title>
<meta charset="UTF-8">
<meta name="generator" content="MediaWiki 1.21.2">
<link rel="shortcut icon" href="../../../common/favicon.ico">
<link rel="stylesheet" href="../../../common/ext.css">
<meta name="ResourceLoaderDynamicStyles" content="">
<link rel="stylesheet" href="../../../common/site_modules.css">
<style>a:lang(ar),a:lang(ckb),a:lang(fa),a:lang(kk-arab),a:lang(mzn),a:lang(ps),a:lang(ur){text-decoration:none}#toc{display:none}.editsection{display:none}
/* cache key: mwiki1-mwiki_zh_:resourceloader:filter:minify-css:7:15cea3ec788a65b5187d4018eed543bf */</style>

<script src="../../../common/startup_scripts.js"></script>
<script>if(window.mw){
mw.config.set({"wgCanonicalNamespace":"","wgCanonicalSpecialPageName":false,"wgNamespaceNumber":0,"wgPageName":"cpp/language/member_functions","wgTitle":"cpp/language/member functions","wgCurRevisionId":60234,"wgArticleId":9015,"wgIsArticle":true,"wgAction":"view","wgUserName":null,"wgUserGroups":["*"],"wgCategories":[],"wgBreakFrames":false,"wgPageContentLanguage":"zh","wgSeparatorTransformTable":["",""],"wgDigitTransformTable":["",""],"wgDefaultDateFormat":"zh","wgMonthNames":["","1月","2月","3月","4月","5月","6月","7月","8月","9月","10月","11月","12月"],"wgMonthNamesShort":["","1月","2月","3月","4月","5月","6月","7月","8月","9月","10月","11月","12月"],"wgRelevantPageName":"cpp/language/member_functions","wgUserVariant":"zh","wgRestrictionEdit":[],"wgRestrictionMove":[]});
}</script><script>if(window.mw){
mw.loader.implement("user.options",function(){mw.user.options.set({"ccmeonemails":0,"cols":80,"date":"default","diffonly":0,"disablemail":0,"disablesuggest":0,"editfont":"default","editondblclick":0,"editsection":0,"editsectiononrightclick":0,"enotifminoredits":0,"enotifrevealaddr":0,"enotifusertalkpages":1,"enotifwatchlistpages":0,"extendwatchlist":0,"externaldiff":0,"externaleditor":0,"fancysig":0,"forceeditsummary":0,"gender":"unknown","hideminor":0,"hidepatrolled":0,"imagesize":2,"justify":0,"math":1,"minordefault":0,"newpageshidepatrolled":0,"nocache":0,"noconvertlink":0,"norollbackdiff":0,"numberheadings":0,"previewonfirst":0,"previewontop":1,"quickbar":5,"rcdays":7,"rclimit":50,"rememberpassword":0,"rows":25,"searchlimit":20,"showhiddencats":0,"showjumplinks":1,"shownumberswatching":1,"showtoc":0,"showtoolbar":1,"skin":"cppreference2","stubthreshold":0,"thumbsize":2,"underline":2,"uselivepreview":0,"usenewrc":0,"watchcreations":0,"watchdefault":0,"watchdeletion":0,
"watchlistdays":3,"watchlisthideanons":0,"watchlisthidebots":0,"watchlisthideliu":0,"watchlisthideminor":0,"watchlisthideown":0,"watchlisthidepatrolled":0,"watchmoves":0,"wllimit":250,"variant":"zh","language":"zh","searchNs0":true,"searchNs1":false,"searchNs2":false,"searchNs3":false,"searchNs4":false,"searchNs5":false,"searchNs6":false,"searchNs7":false,"searchNs8":false,"searchNs9":false,"searchNs10":false,"searchNs11":false,"searchNs12":false,"searchNs13":false,"searchNs14":false,"searchNs15":false,"gadget-MathJax":1,"gadget-ColiruCompiler":1});;},{},{});mw.loader.implement("user.tokens",function(){mw.user.tokens.set({"editToken":"+\\","patrolToken":false,"watchToken":false});;},{},{});
/* cache key: mwiki1-mwiki_zh_:resourceloader:filter:minify-js:7:258d7cd6aa9aa67dee25e01fb6a9e505 */
}</script>
<script>if(window.mw){
mw.loader.load(["mediawiki.page.startup","mediawiki.legacy.wikibits","mediawiki.legacy.ajax"]);
}</script>
<style type="text/css">/*<![CDATA[*/
.source-cpp {line-height: normal;}
.source-cpp li, .source-cpp pre {
	line-height: normal; border: 0px none white;
}
/**
 * GeSHi Dynamically Generated Stylesheet
 * --------------------------------------
 * Dynamically generated stylesheet for cpp
 * CSS class: source-cpp, CSS id: 
 * GeSHi (C) 2004 - 2007 Nigel McNie, 2007 - 2008 Benny Baumann
 * (http://qbnz.com/highlighter/ and http://geshi.org/)
 * --------------------------------------
 */
.cpp.source-cpp .de1, .cpp.source-cpp .de2 {font: normal normal 1em/1.2em monospace; margin:0; padding:0; background:none; vertical-align:top;}
.cpp.source-cpp  {font-family:monospace;}
.cpp.source-cpp .imp {font-weight: bold; color: red;}
.cpp.source-cpp li, .cpp.source-cpp .li1 {font-weight: normal; vertical-align:top;}
.cpp.source-cpp .ln {width:1px;text-align:right;margin:0;padding:0 2px;vertical-align:top;}
.cpp.source-cpp .li2 {font-weight: bold; vertical-align:top;}
.cpp.source-cpp .kw1 {color: #0000dd;}
.cpp.source-cpp .kw2 {color: #0000ff;}
.cpp.source-cpp .kw3 {color: #0000dd;}
.cpp.source-cpp .kw4 {color: #0000ff;}
.cpp.source-cpp .co1 {color: #909090;}
.cpp.source-cpp .co2 {color: #339900;}
.cpp.source-cpp .coMULTI {color: #ff0000; font-style: italic;}
.cpp.source-cpp .es0 {color: #008000; font-weight: bold;}
.cpp.source-cpp .es1 {color: #008000; font-weight: bold;}
.cpp.source-cpp .es2 {color: #008000; font-weight: bold;}
.cpp.source-cpp .es3 {color: #008000; font-weight: bold;}
.cpp.source-cpp .es4 {color: #008000; font-weight: bold;}
.cpp.source-cpp .es5 {color: #008000; font-weight: bold;}
.cpp.source-cpp .br0 {color: #008000;}
.cpp.source-cpp .sy0 {color: #008000;}
.cpp.source-cpp .sy1 {color: #000080;}
.cpp.source-cpp .sy2 {color: #000040;}
.cpp.source-cpp .sy3 {color: #000040;}
.cpp.source-cpp .sy4 {color: #008080;}
.cpp.source-cpp .st0 {color: #008000;}
.cpp.source-cpp .nu0 {color: #000080;}
.cpp.source-cpp .nu6 {color: #000080;}
.cpp.source-cpp .nu8 {color: #000080;}
.cpp.source-cpp .nu12 {color: #000080;}
.cpp.source-cpp .nu16 {color:#000080;}
.cpp.source-cpp .nu17 {color:#000080;}
.cpp.source-cpp .nu18 {color:#000080;}
.cpp.source-cpp .nu19 {color:#000080;}
.cpp.source-cpp .ln-xtra, .cpp.source-cpp li.ln-xtra, .cpp.source-cpp div.ln-xtra {background-color: #ffc;}
.cpp.source-cpp span.xtra { display:block; }

/*]]>*/
</style><style type="text/css">/*<![CDATA[*/
.source-text {line-height: normal;}
.source-text li, .source-text pre {
	line-height: normal; border: 0px none white;
}
/**
 * GeSHi Dynamically Generated Stylesheet
 * --------------------------------------
 * Dynamically generated stylesheet for text
 * CSS class: source-text, CSS id: 
 * GeSHi (C) 2004 - 2007 Nigel McNie, 2007 - 2008 Benny Baumann
 * (http://qbnz.com/highlighter/ and http://geshi.org/)
 * --------------------------------------
 */
.text.source-text .de1, .text.source-text .de2 {font: normal normal 1em/1.2em monospace; margin:0; padding:0; background:none; vertical-align:top;}
.text.source-text  {font-family:monospace;}
.text.source-text .imp {font-weight: bold; color: red;}
.text.source-text li, .text.source-text .li1 {font-weight: normal; vertical-align:top;}
.text.source-text .ln {width:1px;text-align:right;margin:0;padding:0 2px;vertical-align:top;}
.text.source-text .li2 {font-weight: bold; vertical-align:top;}
.text.source-text .ln-xtra, .text.source-text li.ln-xtra, .text.source-text div.ln-xtra {background-color: #ffc;}
.text.source-text span.xtra { display:block; }

/*]]>*/
</style><!--[if lt IE 7]><style type="text/css">body{behavior:url("/mwiki/skins/cppreference2/csshover.min.htc")}</style><![endif]--></head>
<body class="mediawiki ltr sitedir-ltr ns-0 ns-subject page-cpp_language_member_functions skin-cppreference2 action-view cpp-navbar">
        <!-- header -->
        <!-- /header -->
        <!-- content -->
<div id="cpp-content-base">
            <div id="content">
                <a id="top"></a>
                <div id="mw-js-message" style="display:none;"></div>
                                <!-- firstHeading -->
<h1 id="firstHeading" class="firstHeading">非静态成员函数</h1>
                <!-- /firstHeading -->
                <!-- bodyContent -->
                <div id="bodyContent">
                                        <!-- tagline -->
                    <div id="siteSub">来自cppreference.com</div>
                    <!-- /tagline -->
                                        <!-- subtitle -->
                    <div id="contentSub"><span class="subpages">&lt; <a href="../../cpp.html" title="cpp">cpp</a>‎ | <a href="../language.html" title="cpp/language">language</a></span></div>
                    <!-- /subtitle -->
                                                            <!-- bodycontent -->
                    <div id="mw-content-text" lang="zh" dir="ltr" class="mw-content-ltr"><div class="t-navbar" style=""><div class="t-navbar-sep"> </div><div class="t-navbar-head"><a href="../../cpp.html" title="cpp"> C++</a><div class="t-navbar-menu"><div><div><table class="t-nv-begin" cellpadding="0" style="line-height:1.1em;">
<tr class="t-nv"><td colspan="5"> <a href="../language.html" title="cpp/language">语言</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../header.html" title="cpp/header">标准库头文件</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../freestanding.html" title="cpp/freestanding"> 自立与有宿主实现</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../named_req.html" title="cpp/named req">具名要求</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../utility.html#.E8.AF.AD.E8.A8.80.E6.94.AF.E6.8C.81" title="cpp/utility">语言支持库</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../concepts.html" title="cpp/concepts">概念库</a> <span class="t-mark-rev t-since-cxx20">(C++20)</span> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../error.html" title="cpp/error">诊断库</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../utility.html" title="cpp/utility">工具库</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../string.html" title="cpp/string">字符串库</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="https://zh.cppreference.com/w/cpp/container" title="cpp/container">容器库</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../iterator.html" title="cpp/iterator">迭代器库</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../ranges.html" title="cpp/ranges"> 范围库</a> <span class="t-mark-rev t-since-cxx20">(C++20)</span> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../algorithm.html" title="cpp/algorithm">算法库</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../numeric.html" title="cpp/numeric">数值库</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../io.html" title="cpp/io">输入/输出库</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../locale.html" title="cpp/locale">本地化库</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../regex.html" title="cpp/regex">正则表达式库</a> <span class="t-mark-rev t-since-cxx11">(C++11)</span> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../atomic.html" title="cpp/atomic">原子操作库</a> <span class="t-mark-rev t-since-cxx11">(C++11)</span> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../thread.html" title="cpp/thread">线程支持库</a> <span class="t-mark-rev t-since-cxx11">(C++11)</span> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../filesystem.html" title="cpp/filesystem">文件系统库</a> <span class="t-mark-rev t-since-cxx17">(C++17)</span> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="../experimental.html" title="cpp/experimental">技术规范</a> </td></tr>
</table></div><div></div></div></div></div><div class="t-navbar-sep"> </div><div class="t-navbar-head"><a href="../language.html" title="cpp/language">C++ 语言</a></div><div class="t-navbar-sep"> </div><div class="t-navbar-head"><a href="classes.html" title="cpp/language/classes">类</a><div class="t-navbar-menu"><div><div style="display:inline-block">
<div><table class="t-nv-begin" cellpadding="0" style="">
<tr class="t-nv-h2"><td colspan="5">概述</td></tr>
<tr class="t-nv"><td colspan="5"> <a href="classes.html" title="cpp/language/classes">综述</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="class.html" title="cpp/language/class"><code>class</code>/<code>struct</code> 类型</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="union.html" title="cpp/language/union"><code>union</code> 类型</a> </td></tr>
<tr class="t-nv"><td colspan="5"> <a href="injected-class-name.html" title="cpp/language/injected-class-name">注入类名</a> </td></tr>
<tr class="t-nv-h2"><td colspan="5">成员</td></tr>
<tr class="t-nv"><td colspan="5"> <a href="data_members.html" title="cpp/language/data members">数据成员</a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="static.html" title="cpp/language/static">静态成员</a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="this.html" title="cpp/language/this"><code>this</code> 指针</a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="nested_classes.html" title="cpp/language/nested types">嵌套类</a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="member_template.html" title="cpp/language/member template">成员模板</a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="bit_field.html" title="cpp/language/bit field">位域</a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="using_declaration.html" title="cpp/language/using declaration"><code>using</code> 声明</a></td></tr>
<tr class="t-nv"><td colspan="5"> <strong class="selflink">成员函数</strong></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="access.html" title="cpp/language/access">成员访问指定符</a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="constructor.html" title="cpp/language/initializer list">构造函数与成员初始化器列表</a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="data_members.html#.E6.88.90.E5.91.98.E5.88.9D.E5.A7.8B.E5.8C.96" title="cpp/language/data members">默认成员初始化器</a><span class="t-mark-rev t-since-cxx11">(C++11)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="friend.html" title="cpp/language/friend"><code>friend</code> 指定符</a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="explicit.html" title="cpp/language/explicit"><code>explicit</code> 指定符</a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="converting_constructor.html" title="cpp/language/converting constructor">转换构造函数</a></td></tr>
<tr class="t-nv-h2"><td colspan="5">特殊成员函数</td></tr>
<tr class="t-nv"><td colspan="5"> <a href="default_constructor.html" title="cpp/language/default constructor">默认构造函数</a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="copy_constructor.html" title="cpp/language/copy constructor">复制构造函数</a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="move_constructor.html" title="cpp/language/move constructor">移动构造函数</a><span class="t-mark-rev t-since-cxx11">(C++11)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="copy_assignment.html" title="cpp/language/copy assignment">复制赋值运算符</a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="move_assignment.html" title="cpp/language/move assignment">移动赋值运算符</a><span class="t-mark-rev t-since-cxx11">(C++11)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="destructor.html" title="cpp/language/destructor">析构函数</a></td></tr>
<tr class="t-nv-h2"><td colspan="5">继承</td></tr>
<tr class="t-nv"><td colspan="5"> <a href="derived_class.html" title="cpp/language/derived class">基与派生类</a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="ebo.html" title="cpp/language/ebo">空基类优化</a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="virtual.html" title="cpp/language/virtual">虚成员函数</a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="abstract_class.html" title="cpp/language/abstract class">纯虚函数与抽象类</a></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="override.html" title="cpp/language/override"><tt>override</tt></a><span class="t-mark-rev t-since-cxx11">(C++11)</span></td></tr>
<tr class="t-nv"><td colspan="5"> <a href="final.html" title="cpp/language/final"><tt>final</tt></a><span class="t-mark-rev t-since-cxx11">(C++11)</span></td></tr>
</table></div>
</div><div></div></div></div></div><div class="t-navbar-sep"> </div></div>
<p>非静态成员函数是声明于类的<a href="class.html" title="cpp/language/class">成员说明</a>中，不带 <a href="static.html" title="cpp/language/static"><code>static</code></a> 或 <a href="friend.html" title="cpp/language/friend"><code>friend</code></a> 说明符的函数。
</p>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">class</span> S <span class="br0">{</span>
    <span class="kw4">int</span> mf1<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span> <span class="co1">// 非静态成员函数声明</span>
    <span class="kw4">void</span> mf2<span class="br0">(</span><span class="br0">)</span> <span class="kw4">volatile</span>, mf3<span class="br0">(</span><span class="br0">)</span> <span class="sy3">&amp;&amp;</span><span class="sy4">;</span> <span class="co1">// 可为 cv 限定或引用限定</span>
    <span class="kw4">int</span> mf4<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="br0">{</span> <span class="kw1">return</span> data<span class="sy4">;</span> <span class="br0">}</span> <span class="co1">// 可内联定义</span>
    <span class="kw1">virtual</span> <span class="kw4">void</span> mf5<span class="br0">(</span><span class="br0">)</span> final<span class="sy4">;</span> <span class="co1">// 可为虚函数，可使用 final/override</span>
    S<span class="br0">(</span><span class="br0">)</span> <span class="sy4">:</span> data<span class="br0">(</span><span class="nu0">12</span><span class="br0">)</span> <span class="br0">{</span><span class="br0">}</span> <span class="co1">// 构造函数亦是成员函数</span>
    <span class="kw4">int</span> data<span class="sy4">;</span>
<span class="br0">}</span><span class="sy4">;</span>
<span class="kw4">int</span> S<span class="sy4">::</span><span class="me2">mf1</span><span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span> <span class="kw1">return</span> <span class="nu0">7</span><span class="sy4">;</span> <span class="br0">}</span> <span class="co1">// 若不内联定义，则必须定义于命名空间</span></pre></div></div>
<p>允许任何<a href="function.html" title="cpp/language/function">函数声明</a>，并带有仅可用于非静态成员函数的额外语法元素：<a href="final.html" title="cpp/language/final"><code>final</code></a> 与 <a href="override.html" title="cpp/language/override"><code>override</code></a> 说明符，<a href="abstract_class.html" title="cpp/language/abstract class">纯说明符</a>，cv 限定符，引用限定符，以及<a href="constructor.html" title="cpp/language/initializer list">成员初始化列表</a>。
</p><p>可以用以下方式调用类 X 的非静态成员函数
</p>
<div class="t-li1"><span class="t-li">1)</span> 对 X 类型的对象使用类成员访问运算符调用</div>
<div class="t-li1"><span class="t-li">2)</span> 对<a href="derived_class.html" title="cpp/language/derived class">派生</a>自 X 的类的对象调用</div>
<div class="t-li1"><span class="t-li">3)</span> 从 X 的成员函数体内直接调用</div>
<div class="t-li1"><span class="t-li">4)</span> 从派生自 X 的类的成员函数体内调用直接调用</div>
<p>在任何其他类型的对象上调用类 X 的成员函数导致未定义行为。
</p><p>在 X 的非静态成员函数的体内，任何解析为 X 或 X 的某个基类的非类型非静态成员的<a href="expressions.html" title="cpp/language/expressions">标识表达式</a> E（例如一个标识符），均被变换为成员访问表达式 <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="br0">(</span><span class="sy2">*</span>this<span class="br0">)</span>.<span class="me1">E</span></span></span> 除非它已是成员访问表达式的一部分）。模板定义语境中不会发生这种变换，因而可能必须明确地对某个名字前附 <span class="t-c"><span class="mw-geshi cpp source-cpp">this<span class="sy2">-</span><span class="sy1">&gt;</span></span></span>，以使其成为<a href="dependent_name.html" title="cpp/language/dependent name">待决的</a>名字。
</p>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">struct</span> S <span class="br0">{</span>
    <span class="kw4">int</span> n<span class="sy4">;</span>
    <span class="kw4">void</span> f<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
<span class="br0">}</span><span class="sy4">;</span>
<span class="kw4">void</span> S<span class="sy4">::</span><span class="me2">f</span><span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span>
    n <span class="sy1">=</span> <span class="nu0">1</span><span class="sy4">;</span> <span class="co1">// 变换为 (*this).n = 1;</span>
<span class="br0">}</span>
<span class="kw4">int</span> main<span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span>
    S s1, s2<span class="sy4">;</span>
    s1.<span class="me1">f</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span> <span class="co1">// 更改 s1.n</span>
<span class="br0">}</span></pre></div></div>
<p>在 X 的非静态成员函数体内，任何解析到 X 或 X 的某个基类的静态成员、枚举项或嵌套类型的无限定标识，均被变换为对应的有限定标识。
</p>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="kw1">struct</span> S <span class="br0">{</span>
    <span class="kw4">static</span> <span class="kw4">int</span> n<span class="sy4">;</span>
    <span class="kw4">void</span> f<span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>
<span class="br0">}</span><span class="sy4">;</span>
<span class="kw4">void</span> S<span class="sy4">::</span><span class="me2">f</span><span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span>
    n <span class="sy1">=</span> <span class="nu0">1</span><span class="sy4">;</span> <span class="co1">// 变换为 S::n = 1;</span>
<span class="br0">}</span>
<span class="kw4">int</span> main<span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span>
    S s1, s2<span class="sy4">;</span>
    s1.<span class="me1">f</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span> <span class="co1">// 更改 S::n</span>
<span class="br0">}</span></pre></div></div>
<h3><span class="mw-headline" id="const.E3.80.81volatile_.E5.8F.8A.E5.BC.95.E7.94.A8.E9.99.90.E5.AE.9A.E7.9A.84.E6.88.90.E5.91.98.E5.87.BD.E6.95.B0">const、volatile 及引用限定的成员函数</span></h3>
<p>非静态成员函数可声明为带有 const、volatile 或 const volatile 限定符（这些限定符出现在<a href="function.html" title="cpp/language/function">函数声明</a>中的形参列表之后）。cv 限定性不同的函数具有不同类型，从而可以相互重载。
</p><p>在 cv 限定的函数体内，<a href="this.html" title="cpp/language/this"><code>this</code></a> 指针被 cv 限定，例如 <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw4">const</span></span></span> 成员函数中，只能正常地调用其他 const 成员函数。（如果应用了 <a href="const_cast.html" title="cpp/language/const cast"><code>const_cast</code></a>，或通过不涉及 <a href="this.html" title="cpp/language/this"><code>this</code></a> 的访问路径，则仍可调用非 const 成员函数。）
</p>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="co2">#include &lt;vector&gt;</span>
<span class="kw1">struct</span> Array <span class="br0">{</span>
    <a href="../container/vector.html"><span class="kw1269">std::<span class="me2">vector</span></span></a><span class="sy1">&lt;</span><span class="kw4">int</span><span class="sy1">&gt;</span> data<span class="sy4">;</span>
    Array<span class="br0">(</span><span class="kw4">int</span> sz<span class="br0">)</span> <span class="sy4">:</span> data<span class="br0">(</span>sz<span class="br0">)</span> <span class="br0">{</span><span class="br0">}</span>
    <span class="co1">// const 成员函数</span>
    <span class="kw4">int</span> operator<span class="br0">[</span><span class="br0">]</span><span class="br0">(</span><span class="kw4">int</span> idx<span class="br0">)</span> <span class="kw4">const</span> <span class="br0">{</span>
                          <span class="co1">// this 具有类型 const Array*</span>
        <span class="kw1">return</span> data<span class="br0">[</span>idx<span class="br0">]</span><span class="sy4">;</span> <span class="co1">// 变换为 (*this).data[idx];</span>
    <span class="br0">}</span>
    <span class="co1">// non-const member function</span>
    <span class="kw4">int</span><span class="sy3">&amp;</span> operator<span class="br0">[</span><span class="br0">]</span><span class="br0">(</span><span class="kw4">int</span> idx<span class="br0">)</span> <span class="br0">{</span>
                          <span class="co1">// this 具有类型 Array*</span>
        <span class="kw1">return</span> data<span class="br0">[</span>idx<span class="br0">]</span><span class="sy4">;</span> <span class="co1">// 变换为 (*this).data[idx]</span>
    <span class="br0">}</span>
<span class="br0">}</span><span class="sy4">;</span>
<span class="kw4">int</span> main<span class="br0">(</span><span class="br0">)</span>
<span class="br0">{</span>
    Array a<span class="br0">(</span><span class="nu0">10</span><span class="br0">)</span><span class="sy4">;</span>
    a<span class="br0">[</span><span class="nu0">1</span><span class="br0">]</span> <span class="sy1">=</span> <span class="nu0">1</span><span class="sy4">;</span> <span class="co1">// OK：a[1] 的类型是 int&amp;</span>
    <span class="kw4">const</span> Array ca<span class="br0">(</span><span class="nu0">10</span><span class="br0">)</span><span class="sy4">;</span>
    ca<span class="br0">[</span><span class="nu0">1</span><span class="br0">]</span> <span class="sy1">=</span> <span class="nu0">2</span><span class="sy4">;</span> <span class="co1">// 错误：ca[1] 的类型是 int</span>
<span class="br0">}</span></pre></div></div>
 <table class="t-rev-begin">
<tr class="t-rev t-since-cxx11"><td>
<p>非静态成员函数可声明为无引用限定符，带有左值引用限定符（函数名后的 <code>&amp;</code> 记号），或带有右值引用限定符（函数名后的 <code>&amp;&amp;</code> 记号）。在<a href="overload_resolution.html" title="cpp/language/overload resolution">重载决议</a>中，按下列方式对待类 X 的非静态 cv 限定成员函数：
</p>
<ul><li> 无引用限定符：隐式对象形参具有到 cv 限定的 X 的左值引用类型，并额外允许绑定到右值隐含对象实参
</li><li> 左值引用限定符：隐式对象形参具有到 cv 限定的 X 的左值引用类型
</li><li> 右值引用限定符：隐式对象形参具有到 cv 限定的 X 的右值引用类型
</li></ul>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="co2">#include &lt;iostream&gt;</span>
<span class="kw1">struct</span> S <span class="br0">{</span>
    <span class="kw4">void</span> f<span class="br0">(</span><span class="br0">)</span> <span class="sy3">&amp;</span> <span class="br0">{</span> <a href="../io/cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <span class="st0">"lvalue<span class="es1">\n</span>"</span><span class="sy4">;</span> <span class="br0">}</span>
    <span class="kw4">void</span> f<span class="br0">(</span><span class="br0">)</span> <span class="sy3">&amp;&amp;</span><span class="br0">{</span> <a href="../io/cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <span class="st0">"rvalue<span class="es1">\n</span>"</span><span class="sy4">;</span> <span class="br0">}</span>
<span class="br0">}</span><span class="sy4">;</span>
 
<span class="kw4">int</span> main<span class="br0">(</span><span class="br0">)</span><span class="br0">{</span>
    S s<span class="sy4">;</span>
    s.<span class="me1">f</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>            <span class="co1">// 打印“lvalue”</span>
    std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>s<span class="br0">)</span>.<span class="me1">f</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span> <span class="co1">// 打印“rvalue”</span>
    S<span class="br0">(</span><span class="br0">)</span>.<span class="me1">f</span><span class="br0">(</span><span class="br0">)</span><span class="sy4">;</span>          <span class="co1">// 打印“rvalue”</span>
<span class="br0">}</span></pre></div></div>
<p>注意：不同于 cv 限定性，引用限定性不改变 <a href="this.html" title="cpp/language/this"><code>this</code></a> 指针的性质：在右值引用限定的函数中，<span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy2">*</span>this</span></span> 仍是左值表达式。
</p>
</td>
<td><span class="t-mark-rev t-since-cxx11">(C++11 起)</span></td></tr>
</table>
<h3><span class="mw-headline" id=".E8.99.9A.E5.87.BD.E6.95.B0.E5.92.8C.E7.BA.AF.E8.99.9A.E5.87.BD.E6.95.B0">虚函数和纯虚函数</span></h3>
<p>非静态成员函数可声明为<i>虚</i>或<i>纯虚</i>函数。细节见<a href="virtual.html" title="cpp/language/virtual">虚函数</a>与<a href="abstract_class.html" title="cpp/language/abstract class">抽象类</a>。
</p>
<h3><span class="mw-headline" id=".E7.89.B9.E6.AE.8A.E6.88.90.E5.91.98.E5.87.BD.E6.95.B0">特殊成员函数</span></h3>
<p><a href="constructor.html" title="cpp/language/constructor" class="mw-redirect">构造函数</a>和<a href="destructor.html" title="cpp/language/destructor">析构函数</a>是非静态成员函数，在其声明中使用特殊的语法（细节见其相应页面）。
</p><p>一些成员函数是<i>特殊</i>的：在某些环境下，即使用户不定义编译器也会定义它们。它们是：
</p>
<ul><li> <a href="default_constructor.html" title="cpp/language/default constructor">默认构造函数</a>
</li><li> <a href="copy_constructor.html" title="cpp/language/copy constructor">复制构造函数</a>
</li></ul>
 <table class="t-rev-begin">
<tr class="t-rev t-since-cxx11"><td>
<ul><li> <a href="move_constructor.html" title="cpp/language/move constructor">移动构造函数</a>
</li></ul>
</td>
<td><span class="t-mark-rev t-since-cxx11">(C++11 起)</span></td></tr>
</table>
<ul><li> <a href="copy_assignment.html" title="cpp/language/copy assignment">复制赋值运算符</a>
</li></ul>
 <table class="t-rev-begin">
<tr class="t-rev t-since-cxx11"><td>
<ul><li> <a href="move_assignment.html" title="cpp/language/move assignment">移动赋值运算符</a>
</li></ul>
</td>
<td><span class="t-mark-rev t-since-cxx11">(C++11 起)</span></td></tr>
</table>
<ul><li> <a href="destructor.html" title="cpp/language/destructor">析构函数</a>
</li></ul>
<p>特殊成员函数<span class="t-rev-inl t-since-cxx20"><span>以及<a href="default_comparisons.html" title="cpp/language/default comparisons">比较运算符</a></span> <span><span class="t-mark-rev t-since-cxx20">(C++20 起)</span></span></span>是仅有能被<i>预置</i>的函数，即使用 <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy1">=</span> <span class="kw1">default</span></span></span> 替代函数体进行定义（细节见其相应页面）
</p>
<h3><span class="mw-headline" id=".E7.A4.BA.E4.BE.8B">示例</span></h3>
<div class="t-example"><div class="t-example-live-link"><div class="coliru-btn coliru-btn-run-init">运行此代码</div></div>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="cpp source-cpp"><pre class="de1"><span class="co2">#include &lt;iostream&gt;</span>
<span class="co2">#include &lt;string&gt;</span>
<span class="co2">#include &lt;utility&gt;</span>
<span class="co2">#include &lt;exception&gt;</span>
 
<span class="kw1">struct</span> S <span class="br0">{</span>
    <span class="kw4">int</span> data<span class="sy4">;</span>
 
    <span class="co1">// 简单的转换构造函数（声明）</span>
    S<span class="br0">(</span><span class="kw4">int</span> val<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="co1">// 简单的显式构造函数（声明）</span>
    <span class="kw1">explicit</span> S<span class="br0">(</span><a href="../string/basic_string.html"><span class="kw1230">std::<span class="me2">string</span></span></a> str<span class="br0">)</span><span class="sy4">;</span>
 
    <span class="co1">// const 成员函数（定义）</span>
    <span class="kw1">virtual</span> <span class="kw4">int</span> getData<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="br0">{</span> <span class="kw1">return</span> data<span class="sy4">;</span> <span class="br0">}</span>
 
<span class="br0">}</span><span class="sy4">;</span>
 
<span class="co1">// 构造函数的定义</span>
S<span class="sy4">::</span><span class="me2">S</span><span class="br0">(</span><span class="kw4">int</span> val<span class="br0">)</span> <span class="sy4">:</span> data<span class="br0">(</span>val<span class="br0">)</span> <span class="br0">{</span>
    <a href="../io/cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <span class="st0">"ctor1 called, data = "</span> <span class="sy1">&lt;&lt;</span> data <span class="sy1">&lt;&lt;</span> <span class="st0">'<span class="es1">\n</span>'</span><span class="sy4">;</span>
<span class="br0">}</span>
 
<span class="co1">// 此构造函数拥有 catch 子句</span>
S<span class="sy4">::</span><span class="me2">S</span><span class="br0">(</span><a href="../string/basic_string.html"><span class="kw1230">std::<span class="me2">string</span></span></a> str<span class="br0">)</span> <span class="kw1">try</span> <span class="sy4">:</span> data<span class="br0">(</span><a href="../string/basic_string/stol.html"><span class="kw1257">std::<span class="me2">stoi</span></span></a><span class="br0">(</span>str<span class="br0">)</span><span class="br0">)</span> <span class="br0">{</span>
    <a href="../io/cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <span class="st0">"ctor2 called, data = "</span> <span class="sy1">&lt;&lt;</span> data <span class="sy1">&lt;&lt;</span> <span class="st0">'<span class="es1">\n</span>'</span><span class="sy4">;</span>
<span class="br0">}</span> <span class="kw1">catch</span><span class="br0">(</span><span class="kw4">const</span> <a href="../error/exception.html"><span class="kw764">std::<span class="me2">exception</span></span></a><span class="sy3">&amp;</span><span class="br0">)</span> <span class="br0">{</span>
    <a href="../io/cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <span class="st0">"ctor2 failed, string was '"</span> <span class="sy1">&lt;&lt;</span> str <span class="sy1">&lt;&lt;</span> <span class="st0">"'<span class="es1">\n</span>"</span><span class="sy4">;</span>
    <span class="kw1">throw</span><span class="sy4">;</span> <span class="co1">// 构造函数的 catch 子句应该始终再抛出异常</span>
<span class="br0">}</span>
 
<span class="kw1">struct</span> D <span class="sy4">:</span> S <span class="br0">{</span>
    <span class="kw4">int</span> data2<span class="sy4">;</span>
    <span class="co1">// 带默认实参的构造函数</span>
    D<span class="br0">(</span><span class="kw4">int</span> v1, <span class="kw4">int</span> v2 <span class="sy1">=</span> <span class="nu0">11</span><span class="br0">)</span> <span class="sy4">:</span> S<span class="br0">(</span>v1<span class="br0">)</span>, data2<span class="br0">(</span>v2<span class="br0">)</span> <span class="br0">{</span><span class="br0">}</span>
 
    <span class="co1">// 虚成员函数</span>
    <span class="kw4">int</span> getData<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> override <span class="br0">{</span> <span class="kw1">return</span> data<span class="sy2">*</span>data2<span class="sy4">;</span> <span class="br0">}</span>
 
    <span class="co1">// 左值限定的赋值运算符</span>
    D<span class="sy3">&amp;</span> operator<span class="sy1">=</span><span class="br0">(</span>D other<span class="br0">)</span> <span class="sy3">&amp;</span> <span class="br0">{</span>
        <a href="../algorithm/swap.html"><span class="kw1599">std::<span class="me2">swap</span></span></a><span class="br0">(</span>other.<span class="me1">data</span>, data<span class="br0">)</span><span class="sy4">;</span>
        <a href="../algorithm/swap.html"><span class="kw1599">std::<span class="me2">swap</span></span></a><span class="br0">(</span>other.<span class="me1">data2</span>, data2<span class="br0">)</span><span class="sy4">;</span>
        <span class="kw1">return</span> <span class="sy2">*</span>this<span class="sy4">;</span>
    <span class="br0">}</span>
<span class="br0">}</span><span class="sy4">;</span>
 
<span class="kw4">int</span> main<span class="br0">(</span><span class="br0">)</span>
<span class="br0">{</span>
    D d1 <span class="sy1">=</span> <span class="nu0">1</span><span class="sy4">;</span>
    S s2<span class="br0">(</span><span class="st0">"2"</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="kw1">try</span> <span class="br0">{</span>
         S s3<span class="br0">(</span><span class="st0">"not a number"</span><span class="br0">)</span><span class="sy4">;</span>
    <span class="br0">}</span> <span class="kw1">catch</span><span class="br0">(</span><span class="kw4">const</span> <a href="../error/exception.html"><span class="kw764">std::<span class="me2">exception</span></span></a><span class="sy3">&amp;</span><span class="br0">)</span> <span class="br0">{</span><span class="br0">}</span>
    <a href="../io/cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> s2.<span class="me1">getData</span><span class="br0">(</span><span class="br0">)</span> <span class="sy1">&lt;&lt;</span> <span class="st0">'<span class="es1">\n</span>'</span><span class="sy4">;</span>
 
   D d2<span class="br0">(</span><span class="nu0">3</span>, <span class="nu0">4</span><span class="br0">)</span><span class="sy4">;</span>
   d2 <span class="sy1">=</span> d1<span class="sy4">;</span> <span class="co1">// OK ：赋值给左值</span>
<span class="co1">//   D(5) = d1; // 错误：无适合的 operator= 重载</span>
<span class="br0">}</span></pre></div></div>
<p>输出：
</p>
<div dir="ltr" class="mw-geshi" style="text-align: left;"><div class="text source-text"><pre class="de1">ctor1 called, data = 1
ctor2 called, data = 2
ctor2 failed, string was 'not a number'
2
ctor1 called, data = 3</pre></div></div> 
</div>
<h3><span class="mw-headline" id=".E5.8F.82.E9.98.85">参阅</span></h3>
<ul><li><a href="classes.html" title="cpp/language/classes">类</a>
</li><li><a href="data_members.html" title="cpp/language/data members">数据成员</a>
</li><li><a href="static.html" title="cpp/language/static">静态数据成员</a>
</li></ul>

<!-- 
NewPP limit report
Preprocessor visited node count: 1742/1000000
Preprocessor generated node count: 4573/1000000
Post‐expand include size: 46732/2097152 bytes
Template argument size: 13528/2097152 bytes
Highest expansion depth: 14/40
Expensive parser function count: 0/100
-->

<!-- Saved in parser cache with key mwiki1-mwiki_zh_:pcache:idhash:9015-0!*!0!!zh!*!zh!* and timestamp 20190506070750 -->
</div>                    <!-- /bodycontent -->
                                        <!-- printfooter -->
                    <div class="printfooter">
                    来自“<a href="https://zh.cppreference.com/mwiki/index.php?title=cpp/language/member_functions&amp;oldid=60234">https://zh.cppreference.com/mwiki/index.php?title=cpp/language/member_functions&amp;oldid=60234</a>”                    </div>
                    <!-- /printfooter -->
                                                            <!-- catlinks -->
                    <!-- /catlinks -->
                                                            <div class="visualClear"></div>
                    <!-- debughtml -->
                                        <!-- /debughtml -->
                </div>
                <!-- /bodyContent -->
            </div>
        </div>
        <!-- /content -->
        <!-- footer -->
        <div id="cpp-footer-base" class="noprint">
            <div id="footer">
                        <div id="cpp-navigation">
            <h5>导航</h5>
            <ul><li><a href="https://zh.cppreference.com/w/cpp/language/member_functions">Online version</a></li><li>Offline version retrieved 2020-03-14 18:00.</li></ul></div>
                        <ul id="footer-info">
                                    <li id="footer-info-lastmod"> 本页面最后修改于2019年5月5日 (星期日) 22:08。</li>
                                    <li id="footer-info-viewcount">此页面已被浏览过4,155次。</li>
                            </ul>
                    </div>
        </div>
        <!-- /footer -->
        <script>if(window.mw){
mw.loader.state({"site":"loading","user":"missing","user.groups":"ready"});
}</script>
<script src="../../../common/skin_scripts.js"></script>
<script>if(window.mw){
mw.loader.load(["mediawiki.action.view.postEdit","mediawiki.user","mediawiki.page.ready","mediawiki.searchSuggest","mediawiki.hidpi","ext.gadget.MathJax","ext.gadget.ColiruCompiler"], null, true);
}</script>
<script src="../../../common/site_scripts.js"></script>
<script type="text/javascript">
var _gaq = _gaq || [];
_gaq.push(['_setAccount', 'UA-2828341-1']);
_gaq.push(['_setDomainName', 'cppreference.com']);
_gaq.push(['_trackPageview']);
</script><!-- Served in 0.075 secs. -->
	</body>
<!-- Cached 20190507035037 -->
</html>